• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권2호
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• pp.53-59
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• 2005

In this paper, optimum shape design of permanent magnet in slotted type Permanent Magnet Linear Synchronous Motor(PMLSM) is progressed for minimization of detent force owing to structure of slot-teeth and thrust ripple by harmonic magnetic flux of permanent magnet. In order to reduce remodeling time as changing design parameter for Permanent Magnet shape optimization, the moving model node technique was applied. The characteristics of thrust and detent force computed by finite element analysis are acquired equal effect both skewed basic model and optimum model which is optimization of permanent magnet shape. In addition to, thrust per unit volume is improved 4.l2[%] in optimum model.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권2호
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• pp.63-68
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• 2004

This paper presents an approach to optimum design of Moving Magnet Type Linear Oscillatory Actuator(MM-LOA). The Finite Element Method is applied to characteristic parameters for characteristic analysis and in order to reduce modeling time and efforts, the moving model node technique is used. In addition the neural network is used to reduce computational time of analysis according to changing design variable. To confirm the validity of this study, optimum design results are compared with results of analysis procedure that is verified by experiment.

• 한국항공우주학회지
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• 제31권4호
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• pp.26-34
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• 2003

본 논문에서는 이동최소자승 근사법 등의 무요소 근사법을 이용하여 유한요소모델 절점의 연결성과 무관하게 유한요소 절점을 자유로이 활성화시킬 수 있는 절점활성화 기법을 제안하고, 제안된 방법의 타당성을 고찰하기 위해 일관성 조건, 수치해의 유계성 등에 대한 이론적 고찰을 수행한다. 제안된 절점활성화 기법을 이용하면 많은 수의 유한요소 절점 중 관심이 있는 일부 절점만을 선택, 활성화시켜 이들만을 미지수로 이용하여 문제를 해석할 수 있기 때문에 설계 및 재해석을 효율적으로 수행할 수 있다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권10호
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• pp.477-482
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• 2005

In this paper, detent force is minimized using notch and slot-aputure width adjustment in a slotted PMLSM. This time, the moving model node technique has used to reduce the time and the effort for calculation according to changing design parameters. As the result, the detent force of proposed model is decreased from 9.44[N] to 0.97[N] compare with it of basic model greatly. The thrust Is decreased 1.3[$\%$] from 342.07[N] to 337.48[N] a little. The notch is applied to PMLSM simply, the detent force is reduced greatly.

• 한국정보통신학회논문지
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• 제23권7호
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• pp.852-860
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• 2019

본 논문에서는 실내 환경에서 blind 노드가 이동하거나 움직이는 장애물 (ex. 사람)로 인하여 RSSI가 급격히 변하더라도 정확한 blind 노드 측위를 가능하게 하는 exponential moving average (EMA) 필터 적용 적응적 신호 모델 기반 삼변측량기법을 제안한다. 제안된 EMA 필터 적용 적응적 신호 모델 기반 삼변측량기법은 고정된 세 개의 전파 송신 노드와 blind 노드 간 얻어진 RSSI를 통해 blind 노드의 위치를 측정한다. 또한 외부 환경 요인으로 인해 RSSI가 급격히 변화할 경우 non-LOS (NLOS) 환경인 것인지 혹은 blind 노드의 이동으로 인한 RSSI 변화인지를 판별한다. Blind 노드와 전파 송신 노드 사이 경로가 NLOS 환경이 되었다고 판단될 경우 LOS 환경에서 측정된 RSSI를 기반으로 NLOS 환경에서 측정된 RSSI를 보정하여 blind 노드의 좌표를 도출하고, blind 노드가 이동하였다고 판단된다면 실시간 측정된 RSSI를 이용하여 blind 노드의 좌표를 도출한다. 제안 기법은 ZigBee 기반 testbed를 통해 검증하였으며, NLOS 환경 혹은 blind 노드가 이동하는 환경 하에서 기존 기법 대비 개선된 위치 인식 정확도를 가짐을 증명하였다.

• 한국항공우주학회지
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• 제31권4호
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• pp.35-43
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• 2003

본 논문에서는 새로 제안된 절점 활성화 기법을 실제 구현하기 위한 효율적 계산법을 소개하고 각종 수치실험을 수행한다. 포아송 방정식, 2차원 탄성문제, 3차원 탄성문제에 대하여 다양하게 수행된 수치실험을 통하여 절점활성화 이론의 타당성, 수렴성, 및 효율성을 고찰한다. 수렴성, 패치 테스트 등이 포함된 각종 수치실험 결과로부터 절점활성화 기법을 이용하면 정확도의 큰 손실 없이도 많은 수의 유한요소 절점 중 관심이 있는 일부 절점만을 선택, 활성화시켜 이들만을 미지수로 이용하여 효율적으로 문제를 해석할 수 있음을 입증한다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권9호
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• pp.459-464
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• 2006

The detent force by end-effect has an undesired influence on moving coil type Permanent Magnet Linear Synchronous Motor(PMLSM). So, the reduction of detent force by end-effect is especially required for the improvement of thrust characteristics. In this paper, in order to reduce detent force by end-effect, the auxiliary-teeth is installed at the end part of mover. It is also analyzed by Finite Element Analysis(FEA) and optimized by using neural network. By comparison, the detent force is reduced about 41.4[%] comparing to that of basic model.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.77-80
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• 2001

The element-free Galerkin (EFG) method is one of meshless methods, which is an efficient method of modeling problems of fluid or solid mechanics with complex boundary shapes and large changes in boundary conditions. This paper discusses the theory of the EFG method and its applications to modeling of groundwater flow. In the EFG method, shape functions are constructed based on the moving least square (MLS) approximation, which requires only set of nodes. The EFG method can eliminate time-consuming mesh generation procedure with irregular shaped boundaries because it does not require any elements. The coupled EFG-FEM technique was introduced to treat Dirichlet boundary conditions. A computer code EFGG was developed and tested for the problems of steady-state and transient groundwater flow in homogeneous or heterogeneous aquifers. The accuracy of solutions by the EFG method was similar to that by the FEM. The EFG method has the advantages in convenient node generation and flexible boundary condition implementation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.40-42
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• 2005

In this paper, thrust ripple is minimized using notch and slot-aperture width adjustment in a slotted PMLSM and then optimal design was achieved by using a neural network. This paper has used the moving model node technique to reduce the time and the effort for calculation according to changing design parameters. As the result, the detent force of optimal model is decreased from 9.44[N] to 0.97[N] greatly compare with it of basic model. The thrust is decreased 1.3[%] from 342.07[N] to 337.48[N] a little.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.486-489
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• 2006

This paper presents a newly proposed object-oriented finite element framework and its applications on dynamic analysis of plate girder bridge. The developed framework supports various types of finite elements, materials, constraints, loads, and solution methods. One major feature different from other object-oriented finite element programs is that static model and dynamic state can be easily read from or written to a file. In addition, the framework supports efficient DOF pattern handling for a node connecting elements with different DOF patterns, new multi-point constraint handling, and various scripting languages for easy use of the library. In order to show the applicability to dynamic analysis, dynamic moving load analysis on plate girder bridge is performed.